The present invention relates generally to photographic apparatus and more particularly to a mechanism whereby the opening of a shutter is synchronized with the actuation of a light emitting element. The invention has applicability to the synchronization of a camera shutter with a source of artificial illumination such as a flash lamp or the like. The invention has particular value with a camera in which the shutter is actuated by a shutter actuating member utilizing the phenomenon of magnetic repulsion between magnets carried by the shutter and shutter actuating members.
In the photographic field it has long been recognized that in order to obtain optimum results with ignition-type artificial illumination rather precise coordination between the opening of the camera shutter and generation of the artificial illumination is required. Various mechanisms for providing such synchronization of the shutter and light souce have been known heretofore. U.S. Pat. Nos. 1,989,109 issued Jan. 29, 1935 to R. I. Munder 2,443,208 issued June 15, 1948 to H. O. Thralls and 4,023,192 issued May 10, 1977 to Horst Simon et al. are representative of prior devices which employ a combination of movable mechanical elements and switches designed to ignite a flash element upon predetermined movement of the shutter member. Such mechanical structures function in a generally satisfactory manner; however, the mechanisms are relatively complex, the components are subject to considerable wear, and great reliance is placed upon spring elements which, through repeated use, are subject to failure due to fatigue. Time consuming maintenance and repair consequently is necessary in order to preserve the degree of synchronization intended between shutter movement and flash actuation.
In an effort to avoid at least the principal shortcomings of the prior mechanical devices, resort has been had to electronic synchronization devices. For example, Canadian Pat. No. 811,977 issued May 6, 1969 to AGFA-Gevaert Aktiengesselschaft discloses an arrangement for synchronizing the operation of a camera shutter and a source of artificial light. In accordance with the patented disclosure, an electronic circuit includes a thyristor and an induction coil connected in series and a diode connected in parallel across the coil. A light source is connectable in series with the electronic circuit. The coil is wound upon one pole of a horseshoe magnet and a pin made of ferromagnetic material is caused to move with the shutter member and to traverse the gap between the poles of the horseshoe magnet. The pin enters the gap when the shutter opens thereby changing the magnetic flux and resulting in the transmission of a positive voltage impulse by the coil which activates the electronic circuit completing the circuit to the light source. Although the arrangement does indeed overcome certain of the disadvantages inherent in mechanical synchronization systems, the introduction of electronic components increases original and replacement costs and requires a skilled mechanic to ascertain the reason for any malfunction and to then effectuate the repair and/or component replacement needed.